Keiichi Hanaki

Compound heterozygous mutations of cytochrome P450 oxidoreductase gene (POR) in two patients with Antley-Bixler syndrome.

Antley–Bixler syndrome (ABS) is characterized by skeletal defects including craniosynostosis and radiohumeral synostosis. Although mutations in the FGFR2 gene have been found in some patients called ABS, genetic heterogeneity of this syndrome has been proposed. We have previously reported three ABS patients with unique abnormalities in steroidogenesis (apparent decreased activity of 17α‐hydroxylase, 17,20‐lyase, and 21‐hydroxylase). Decreased activity of lanosterol 14α‐demethylase has also been described in an ABS patient. Since all these enzymes require cytochrome P450 oxidoreductase (encoded by POR) as an electron donor, we studied POR in two unrelated ABS patients with abnormal steroidogenesis. Direct sequencing of POR revealed that both patients had compound heterozygous mutations (1329insC and R454H in a male patient, 1698insC and R454H in a female patient). The two insertional mutations were assumed to generate truncated and unstable mRNAs. The R454H mutation was assumed to be deleterious because the R454 resides in the FAD‐binding domain and is highly conserved among diverse species. Our results demonstrate that mutations in POR cause the ABS phenotype with autosomal recessive inheritance and with characteristic abnormalities in steroidogenesis.

Criteria for medical intervention in obese children: A new definition of ‘Obesity disease’ in Japanese children

The Committee of the Japan Society for the Study of Obesity reported the new criteria for ‘obesity disease’ for Japanese adults in 2000. We defined the criteria for the diagnosis of obesity in children with medical problems, corresponding to the ‘obesity disease’ criteria in adults. Obesity in childhood was defined as follows: percentage of overweight (POW) and body fat exceeded the criteria. ‘Obesity disease in childhood’ was defined as obesity associated with health or medical problems, and with indications for medical intervention. Medical problems with indications for immediate intervention were grouped as A problems, which consisted of (i) hypertension; (ii) sleep apnea or hypoventilation; (iii) Type 2 diabetes mellitus or impaired glucose tolerance; and (iv) increased waist circumference or accumulation of visceral adipose tissue. Metabolic derangements or equivalent associated with obesity were grouped as B problems: (i) liver dysfunction; (ii) hyperinsulinemia; (iii) hypercholesterolemia; (iv) hypertriglyceridemia; (v) low serum high‐density lipoprotein cholesterol; (vi) acanthosis nigricans, and (vii) hyperuricemia. Obese children over 5 years of age with following conditions were diagnosed as ‘obesity disease in childhood’: (i) any ‘A problem’, (ii) POW ≥ 50% and any ‘B problem’, or (3) POW < 50% and more than one ‘B problem’ or equivalent. We decided to take physicosocial problems related to obesity into consideration as the criteria. The resultant criteria are proposed by the Committee for Research of Appropriate Body Build in Children * .

Cytochrome P450 oxidoreductase deficiency: identification and characterization of biallelic mutations and genotype-phenotype correlations in 35 Japanese patients.

CONTEXT Cytochrome P450 oxidoreductase (POR) deficiency is a rare autosomal recessive disorder characterized by skeletal dysplasia, adrenal dysfunction, disorders of sex development (DSD), and maternal virilization during pregnancy. Although multiple studies have been performed for this condition, several matters remain to be clarified, including the presence of manifesting heterozygosity and the underlying factors for clinical variability. OBJECTIVE The objective of the study was to examine such unresolved matters by detailed molecular studies and genotype-phenotype correlations. PATIENTS Thirty-five Japanese patients with POR deficiency participated in the study. RESULTS Mutation analysis revealed homozygosity for R457H in cases 1-14 (group A), compound heterozygosity for R457H and one apparently null mutation in cases 15-28 (group B), and other combinations of mutations in cases 29-35 (group C). In particular, FISH and RT-PCR sequencing analyses revealed an intragenic microdeletion in one apparent R457H homozygote, transcription failure of apparently normal alleles in three R457H heterozygotes, and nonsense mediated mRNA decay in two frameshift mutation-positive cases examined. Genotype-phenotype correlations indicated that skeletal features were definitely more severe, and adrenal dysfunction, 46,XY DSD, and pubertal failure were somewhat more severe in group B than group A, whereas 46,XX DSD and maternal virilization during pregnancy were similar between two groups. Notable findings also included the contrast between infrequent occurrence of 46,XY DSD and invariable occurrence of 46,XX DSD and pubertal growth pattern in group A mimicking that of aromatase deficiency. CONCLUSIONS The results argue against the heterozygote manifestation and suggest that the residual POR activity reflected by the R457H dosage constitutes the underlying factor for clinical variability in some features but not other features, probably due to the simplicity and complexity of POR-dependent metabolic pathways relevant to each phenotype.

POR R457H is a global founder mutation causing Antley–Bixler syndrome with autosomal recessive trait

Masanori Adachi,* Yumi Asakura, Mari Matsuo, Toshiyuki Yamamoto, Keiichi Hanaki, and Wiebke Arlt Department of Endocrinology & Metabolism, Clinical Research Institute, Kanagawa Children’s Medical Center, Yokohama, Japan Department of Medical Genetics, Clinical Research Institute, Kanagawa Children’s Medical Center, Yokohama, Japan Department of Women’s & Children’s Family Nursing, Faculty of Medicine, Tottori University, Tottori, Japan Division of Medical Sciences, Institute of Biomedical Research, The Medical School University of Birmingham, Birmingham, UK

Novel missense mutation in the IGF‐I receptor L2 domain results in intrauterine and postnatal growth retardation

IGFs play key roles in intrauterine and postnatal growth through the IGF‐I receptor (IGF‐IR). We identified a family bearing a new heterozygous missense mutation at the L2 domain of IGF‐IR (R431L).

Eating Attitudes Test in Boys and Girls Aged 6–18 Years: Decrease in Concerns with Eating in Boys and the Increase in Girls with Their Ages

Concerns with eating were studied in 130 Japanese boys and 125 girls aged 6-18 years using the Simplified Eating Attitudes Test (s-EAT). The s-EAT scores in girls slightly increased with age. The mean scores in girls at age 10 years or older were significantly higher than in boys of the same age, suggesting that pubertal girls have more concerns with eating. On the other hand, s-EAT scores in boys that were not overweight decreased as they grew older, contributing, at least partly, to the sexual difference in eating behavior. The mean scores in overweight boys were higher than in boys that were not overweight. The score in boys correlated significantly with weight though there was no significant correlation in girls. These results suggest that, in addition to increased concerns with eating in girls, decreased concerns with age in boys is one of the causes of the sexual difference in eating behavior, especially during puberty. Eating behaviors in girls seem to be less influenced by changes in body weight than in boys.

Abnormal perception of body weight is not solely observed in pubertal girls: incorrect body image in children and its relationship to body weight

Perceived actual body weight and perceived ideal weight were assessed in 255 Japanese children and adolescents (130 boys, 125 girls) aged 6 years through 18 years using the drawing test to clarify whether they wanted to be thinner or to gain weight. More than half (68%) of the girls attending high school and 41% of the elementary school girls perceived their ideal weight to be less than the standard. The mean difference between the perceived actual weight and the ideal weight was positive in the high school girls of normal weight as well as in the overweight girls, meaning that even the normal‐weight girls wanted to lose weight. The difference was also slightly positive in the underweight girls. The difference in the high school boys was negative, demonstrating that they wished to gain weight. It is suggested that girls want to lose weight even before adolescence; this tendency becomes more prominent in the high school period and is mostly unrelated to their own weight.

Prevalence of Obesity, Leanness and Anorexia nervosa in Japanese Boys and Girls Aged 12–14 Years

Body weight and height of Japanese boys and girls aged 12-14 years were measured to calculate the prevalence of obesity, leanness and anorexia nervosa. In boys, the prevalence of obesity as well as leanness was significantly higher in the areas where population density was lower and among the boys who attended schools with smaller numbers of pupils. In the girls, these findings were similar to the boys. On the other hand, anorexia nervosa was found in girls only more commonly in the areas with higher population density and in the larger schools. These results suggest that higher prevalence of obesity in certain subjects may be associated with increased numbers of leanness but not with anorexia nervosa.

Aromatase Excess Syndrome: Identification of Cryptic Duplications and Deletions Leading to Gain of Function of CYP19A1 and Assessment of Phenotypic Determinants

CONTEXT Aromatase excess syndrome (AEXS) is a rare autosomal dominant disorder characterized by gynecomastia. Although cryptic inversions leading to abnormal fusions between CYP19A1 encoding aromatase and its neighboring genes have been identified in a few patients, the molecular basis remains largely unknown. OBJECTIVE The objective of the study was to examine the genetic causes and phenotypic determinants in AEXS. PATIENTS Eighteen affected males from six families participated in the study. RESULTS We identified three types of heterozygous genomic rearrangements, i.e. a 79,156-bp tandem duplication involving seven of 11 noncoding CYP19A1 exons 1, a 211,631-bp deletion involving exons 2-43 of DMXL2 and exons 5-10 of GLDN, and a 165,901-bp deletion involving exons 2-43 of DMXL2. The duplicated exon 1 functioned as transcription start sites, and the two types of deletions produced the same chimeric mRNA consisting of DMXL2 exon 1 and CYP19A1 coding exons. The DMXL2 exon 1 harbored a translation start codon, and the DMXL2/CYP19A1 chimeric mRNA was identified in only 2-5% of CYP19A1-positive transcripts. This was in contrast to the inversion-mediated chimeric mRNA that had no coding sequence on the fused exon 1 and accounted for greater than 80% of CYP19A1-positive transcripts. CYP19A1 was expressed in a limited number of tissues, whereas its neighboring genes involved in the chimeric mRNA formation were expressed widely. CONCLUSIONS This study provides novel mechanisms leading to gain of function of CYP19A1. Furthermore, it appears that clinical severity of AEXS is primarily determined by the tissue expression pattern of relevant genes and by the structural property of promoter-associated exons of chimeric mRNA.

HLA-class II and class I genotypes among Japanese children with Type 1A diabetes and their families

Sugihara S, Ogata T, Kawamura T, Urakami T, Takemoto K, Kikuchi N, Takubo N, Tsubouchi K, Horikawa R, Kobayashi K, Kasahara Y, Kikuchi T, Koike A, Mochizuki T, Minamitani K, Takaya R, Mochizuki H, Nishii A, Yokota I, Kizaki Z, Mori T, Shimura N, Mukai T, Matsuura N, Fujisawa T, Ihara K, Kosaka K, Kizu R, Takahashi T, Matsuo S, Hanaki K, Igarashi Y, Sasaki G, Soneda S, Teno S, Kanzaki S, Saji H, Tokunaga K, Amemiya S, and The Japanese Study Group of Insulin Therapy for Childhood and Adolescent Diabetes (JSGIT). HLA‐class II and class I genotypes among Japanese children with Type 1A diabetes and their families.